The purpose for the DHS buying the sniper bullets is for preemptive crowd control.

They likely figure as follows: rather than dealing with a massive protesting crowd in the streets - prevent this to begin with by keeping them in their homes to begin with.

They position snipers all over high places, or in choppers overhead, in any major metropolitan area - they publicize this fact on state T.V. - then when anyone so much as sticks their head outside of their window - well, that's it for them. Pictures for all to witness at noon.

Their idea is to instill such terror into the minds of the masses with this stratagem - that nobody will dare violate a curfew to congregate to protest = city locked down. Finito. This is why they say 'no warning shot is to be given.' Their purposes is not to protect, not even to warn, but to instill terror in the masses - by the threat of a curfew violator being killed by a silent stealthy unseen foe half a mile away. Here one moment - gone the next instant. Fear of the unseen mortal threat.

Likely, they have special sniper response squadrons ready to fly to any rioting city needing lockdown. See?
Look for such specialized military units, and for increased funding and training for such. Maybe open up a line on your show for one patriot among them to call in?